Method of conditioning metal sheets, strips, rods, and the like



Jan. 19. 1954 R. O. PETERSON METHOD OF 2,666,282 CONDITIONING METALSHEETS, STRIPS, RODS, AND

THE LIKE Filed April 19'. 1951 5 Sheets-Sheet l O O O O O O O INVENTOR.

J MYIMD4 ATTORNEYS Jan. 19, 1954 Filed April 19, 1951' R. O. PETERSONMETHOD OF CONDITIONING METAL SHEETS, STRIPS, RODS, 'AND THE LIKE 3Sheets-Sheet 2 I INVENTOR. RUBEN OJPETERSO/V OLM M 6'7 7 OQNEYS.

ONDITIONING METAL SHEETS, STRIPS, RODS, AND

THE LIKE 3 Sheets-Sheet 5 Filed April 19, 1951 .2 v: 000000000 Q Q A, N:.w: 8 .E

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0 O 0 m: m9 .,o O mo. g 0 J R l 00000090 8. 8 KW r, 0 og mm 9 o 09 mm owQ INVENTOR. RUBEN O.PETERSON Jaw ATTORNEYS Patented Jan. 19, 1954METHOD OF CONDITIONING METAL SHEETS, STRIPS, RODS, AND THE LIKE Ruben 0.Peterson, University Heights, Ohio, as-

' signor to The Osborn Manufacturing Company,

Cleveland, Ohio, a corporation of Ohio Application April 19, 1951,Serial No. 221,906

' 7 Claims. 1 The present invention relating as indicated to theconditioning of metal sheets, strip, rod and the like has moreparticularregard to means and methods for attaining such beneficiatingeffects as the removal of scale and other closely adherent coatings andsmall slivers, and the rounding of the sharp edges of small pits andscratches, and reducing differences in hardness and associated physicalqualities of small adjacent surface areas and small adjacent subsurfacecomponent formations, and cleaning and polishing the surface, andreducing surface tension on such articles by brushing action and by theconjoint action, on the surface being treated, of a brush and ofauxiliary materials such as abrasive, peening pellets, cleaning andcoating materials.

' The addition of an abrasive to a brushing operation in order to cleanthe surface of a metal sheet or like article by an ordinary scouringoperation is, of course, well known. Thus, floors have been long cleanedand polished in this manner. It has also been proposed to clean sheetmetal plates (see Patent No. 451,263 to Buckman) by similarly supplyingan abrasive, e. g. sand, to the surface of the sheet in advance of theapplication thereto of a rotary brush. However, such simple scouringtreatment has not proved effective for the removal of closely adherentoxide coatings, such as heat formed scale, from sheet or strip steel orrod, in order to prepare such metal for further reduction as by rollingor drawing or to prepare the surface of such metal for plating withanother metal, such as tin or zinc, or to receive and retain a paint,lacquer, or enamel coating, without employing more costly, objectionableand less beneficial pickling processes.

An aspect of the continuing roblem presented, of scale removal by abrushing operation, is evidenced by Patents Nos. 1,440,619 to Noyes eta1. and 2,335,196 to Pecsok, which respectively disclose differentmethods of applying a brush to the surface of a sheet in an endeavor tosecure complete scale removal. But other aspects include the removal ofsmall slivers and the sharp edges of pits and scratches which are notremoved by prior methods and which when not removed become, uponsubsequent rolling, drawing, or the like, the sources of miniature seamsand the starting points of fractures when an articlemade from the metalsheet, strip or rod is subjected to stresses of manufacture and use.Also a phase of the problem involves the minimizing of differences inhardness and associated physical qualities of small adjacent surfaceareas and small adjacent subsurface component formations, whichdifferences, when permitted to become exaggerated, reduce the facilitywith which the metal may be worked and reduce someof the desirablequalities of the articles made therefrom. Some commonly used methods andmeans, suchas for example scale-breaking and subsequent pickling toremove the scale, exaggerate such differences and therefore have seriousdetrimental effects while achieving the main objective.

As indicated above, one object of the present invention is to combinebrushing action with application of an abrasive material in such amanner as will effectually accomplish the removal of scale, smallslivers, and other objectionable surface irregularities from metalsheets, strip, rod and similar articles. I have discovered that if suchabrasive material be forcibly discharged onto the surface of a sheetsimultaneously with the application of a brush thereto or immediately inadvance of such application, not only is the cleaning action greatlyimproved but the power required for brushing greatly reduced. I havefurther discovered that where, as will be desirable, a rotary brush isemployed, such brush itself may be utilized thus forcibly to discharge,by centrifugal action, the abrasive material onto the surface of thesheet without detracting from, but on the contrary greatly increasing,the chiciency of the brushing action proper.

While in the case of metal sheets and strip,

they will at times desirably be arcuately flexed to present a convexsurface to the brush, as taught by the above-cited Pecsok patent, thepresent improved method of conditioning sheets, etc., is not limited tosuch procedure but may be utilized in connection with fiat sheets,strips or'like articles or with sheets or strips arcuately flexed topresent a concave surface to the brush. Furthermore, in such method Imay utilize abrasive material either in dry granular form havingvariousdegrees of fineness or such abrasive may be carried by a suitableliquid vehicle. The invention further comprehends improved means forconducting the abrasive in either such form to the brush in such manneras to utilize the centrifugal action of the latter to forcibly dischargethe abrasive onto the sheet.

To the accomplishment of the foregoing and related ends, said invention,then, consists of the means hereinafter fully described and particular-7 1y pointed out in the claims, the annexed drawings and the followingdescription setting forth in detail certain means and one mode ofcarrying out the invention, such disclosed means and modes illustrating,however, but one of various ways in which the principle of the inventionmay be used.

In said annexed drawings: v

Fig. 1 is a diagrammatic side elevational view of one form of apparatusconstructed in ac- 3 cordance with the present invention and showing ametal strip in process of being acted upon thereby;

Fig. 2 is a central longitudinal section of one of the brushes, shown asbeing utilized in such apparatus, wherein the centrifugal action of thebrush is utilized to discharge granular abrasive material onto the sheetbeing treated;

Fig. 2a shows a detail of Fig. 2 on larger scale;

Fig. 3 is a transverse section of such brush, the plane of the sectionbeing indicated by the line 3-3, Fig. 2; a

Fig. 4 is a diagrammatic side elevational view of one form of apparatusconstructed in ac cordance with my invention and showing a metal stripin process of being acted upon thereby.

Referring to the construction of apparatus illustrated in Fig. 1, suchapparatus will be seen to comprise two rolls l and 2, about which themetal strip S is passed in such manner that each side of the strip willbe respectively subjected to the action of rotating cylindrical brushes3 and 4 which are disposed with their axes respectively parallel to thecorresponding rolls (which may be disposed at desired angles to thelongitudinal axis of the strip) and so spaced in relation thereto thatthe brushes will contact with the arcuately flexed portions of the sheetas it passes over and is supported by said rolls respectively. The rollsI and 2 of course are rotated in the same direction as that in which thesheet S moves in passing thereover and the brushes 3 and 4 will berotated in a direction opposite to that of the rolls, i. e. in the samedirection as that in which the strip moves while in contact with thelatter, or in a reverse direction, or alternately first in one directionand then in another for short periods of time. Certain brush materialswork best when they are continually sharpened by alternately operatingthe brush first in one direction and then in the other. Also, thedirection of operation of a brush determines which sides of pits orscratches and corresponding sharp edges of which will be mosteffectively rounded by a given brush. It is, therefore, desirable to employ several brushes and to have their respective directions ofoperation so adjusted and periodically alternated as to have theireffective operational directions adjusted to several different relatedangles. be power driven, either by direct motor drive or otherwise asfound desirable or convenient, the brushes preferably being rotatedrapidly, for example at approximately 3000 R. P. M. in the case of a 12in. diameter brush, which will be approximately equal to an average of9000 F. P. M. during the useful life of the brush, while the strip ofcourse moves at a much lower speed, relative to the speed at which thecontacting brush surfaces travel. Brushes larger than 12 inches indiameter will often be preferred.

For the purpose of feeding the sheet to the rolls I and 2, as it isreceived from roller conveyor 5 it passesbetween relatively adjustablebending rolls 6, I and 8 which serve to arcuately bend the strip to acurve of somewhat greater diameter than that of roll I. .The strip thenpasses between guide rollers 9 and 10, which direct it intosubstantially tangential relationship to the surface of the rolldirectly opposite brush 3. Beyond the roll I the strip passes betweenrollers II and 12, which are disposed in a relationship to said rollcomplementary to that of rollers 9 and I0.

As a result of the disposition of the two pairs The rolls and brusheswill 1 of guide rollers the area of contact of the sheet S on itsconcave side with the roll I is limited substantially to that of thearea of contact of its convex side with the opposed rotating brush 3.The brush will be set no more tightly against the sheet or strip S thannecessary to obtain the desired efiect, since the coefficient offriction be tween the brush and the strip increases more rapidly thanthe square of the pressure, and the power consumption is of course afactor of importance. Over-brushing of the metal surface furthermore mayhave detrimental effects in forming characteristic irregularities andremoving and displacing too much metal.

Directly below the point of tangency of roll 5 and brush 3 is an exhaustcollector l3 adapted to receive the particles of scale removed from thesheet by the action of brush 3 as well as additional granular abrasivematerial which, as will presently be described, will be supplied to thebrush for use as in the treatment of the sheet. A suction fan 14,connected with collector I3, serves to convey the abrasive including ofsuch scale along a duct I5 in which is interposed a screen [6 wherebythe larger particles are caught and collected in a trap ll. Theremaining, finer particles of scale are delivered by duct 15 to a hopper18 located conveniently adjacent brush 3 from which such abrasiveparticles may be supplied to the brush in the manner presently to bedescribed.

Returning to the progress of the sheet S, after leaving guide rollers IIand 12 it then continues between bending rolls 20, 21 and 22, whereby itis arcuately bent in the opposite direction from that given it by thefirst-mentioned set of bending rolls and caused to tangentially engageroll 2 where its other side, now convex, is subjected to the action ofbrush 4. Disposed on opposite sides of roll 2 are complementary pairs ofguide rollers 23, 24 and 25, 26 which, like the previously mentionedpairs of guide rollers, serve to limit the area of contact which thestrip or sheet S has with roll 2. Finally, the sheet is received betweenstraightening rolls 21, 28 and 29 which straighten the strip and enableit to continue in its original direction along the roller conveyor 30.Associated with brush 4 is a collector 3| and suction fan 32, which'areconnected with a suitable hopper associated with brush 4 through a duct(not shown), in the same manner asin the case of the collector andhopper associated with brush 3. If brushes 3 and i are adapted to beperiodically reversed in operation, as preferred, then of course similarcollectors should also be provided at the other side of the brush.

As indicated, the rotary brushes 3 and 3 which are disposed to operateon the convexly flexed surface of the sheet as it moves through theapparatus will in effect be duplicates of each other, being designed toperform the same operation on opposite sides of such sheet; furthermore,each such brush is so constructed as to adapt the same to forcefullyproject abrasive material onto such convexly flexed surface of thesheet. A preferred construction of brush designed to operate in themanner just referred to is shown in Figs. 2, 3 and 2a, which will now bedescribed. As there shown, the body of the brush comprises twooppositely disposed hub members 35 and 36 respectively provided withbearing sleeves 35a and 36a whereby said members may be rotatablysupported. in suitable journals. Fitted to said hub members is acylindrical shell 31 that is provided with a suitable number of properlyspaced perforations 38 "manner.

through the portion thereof lying between the hub members to permit thedischarge outwardly through such shell of abrasive material supplied tothe interior thereof. Mounted in turn on shell '31 is "a body 39 ofradially extending stranded brush material. This material may constistof crimped wire of varyingdegrees of fineness, or

any of the other materials usually employed in brushing operations ofthe character involved, and may be secured to the shell in any approvedAs illustrated, such brush material is disposed in the form of doubledlayers held by a retaining Wire or ring 40 in a channel form base 4|which may be either in the form of an annulus or wound helically aboutthe shell. Retaining rings 42, 42 held in place by means of lock rings43 'threaded on the respective ends of the shell press against thecorresponding sides of the 'assembled body of brush material and serveboth to'secure the latter to the shell and compact the same to thedesired degree.

Where the brush material is held in a channel form base 4|, the sides ofthe latter, as shown in Fig. 2a, are formed with alternate depressedareas and intermediate lands so that radial passages will be leftbetween adjacent bases (or sections of the base Where helically wound onthe shell) and the number and disposition of the perforations 38 in theshell 3'! will be such that a'substantial portion, if not all, of thepassages thus provided will coincide in location with such perforationsso that abrasive supplied in the manner previously referred to may passthrough the latter and such passages and thence outwardly in between thestranded brush material. relatively free flow of abrasive is furtherfacilitated by rounding the lower corners of the channel form bases sothat circumferential passages are provided between adjacent bases whichwill further insure connections between the per- 'forations in the shelland such radial passages.

The specific construction just described, whereby provision is made forthe flow of abrasive from within the shell 31 into the body of strandedbrush material, forms the subject matter of my Patent No. 2,409,309,dated October 15, 1946, and it will be understood that where differentmethods of attaching the stranded brushmaterial to the brush body areemployed, other means for providing for such flow may require to beused. In

other words, the illustrated construction is to be considered merely asconstituting one form of brush body wherein provision is made for suchflow of abrasive from the interior thereof radially outwardly into thestranded brush material.

Further referring to Figs. 2 and 3, it will be seen that a tubular shaft45 extends axially through the body of the brush, the ends of such shaftprojecting beyond the respective hubs 35 and 36. The intermediateportion of the shaft, i. e. that lying between such hubs within shell31, is provided with a longitudinally aligned series of apertures 46through which abrasive or other flowable material may be introduced intothe hollow interior of the brush body. Such material may be suppliedfrom any suitable source to the tube through either end thereof, theright-hand end being shown as selected for the purpose in Fig. 2.A'solid rod 41 inserted in the other end of the tubular shaft serves toclose off such end and being reciprocable said rod may be utilized forthe further purpose of cleaning out the in- Such terior of the shaftshould it, or the openings 46 7 therein, become clogged.

Tubev 45 is not directly in contact with the openings in the hubs and35, but the portion thereof lying within hub 35 is surrounded by asecond tubular shaft, or rather sleeve, 48 which serves as a closefitting bushing within which such shaft may be angularly adjusted, i. e.rotated about its axis so as correspondingly to vary the angularposition of the series of perforations in relation to the axis of theshaft. The portion of the shaft 45 which lies within hub 36 is similarlysurrounded by a closel fitting tubular shaft 49 and said shaft 49 is inturn surrounded by a second tubular shaft or sleeve 5d, the function ofwhich is the same as that of sleeve 48 except that, as indicated, saidshaft s9 is interposed therebetween and the innermost tubular shaft 45.Said shaft 49 projects into the hollow interior of the brush body anddesirably includes an axially spaced extension in the form of a separatering 5| that lies adjacent the inner face of hub 35, and fixedlyattached to these portions of said shaft 49 is a radially projectingwiper 52. While the latter may take on various forms, it will desirablyconsist, as best shown in Fig. 3, of a straight channelform base 53,similar to the base employed to hold the brush material comprised inbrush body 39, and a doubled layer of stranded brush material which issecured in such base just as the previously mentioned brush material issecured in the channel bases 4!. The wiper thus constructed extendssubstantially across the space within shell 31 lying between the twohubs 35 and 36 and is of such radial extent that its outer edge, which,where the blade is formed of stranded brush material, will consist ofthe ends of such strands, will frictionally engage with the inner faceof said shell.

Shaft 49 is normally held against rotation by suitable means and as aresult rotation of the inner face of the shell 31 about such wiperserves to clear the perforations 3B in such shell should they becomecloggediyvhile the brush is in use. However, when desired, tubular shaft49 which carries the wiper 52 may be rotated, or rather adjustedangularly, about the axis of said shaft so as to correspondingly varythe angular position of the wiper within said shell. Any suitable meansmay be provided for thus rotatably adjusting said shaft 45 and forretaining the same against rotation as desired, e. g. a worm gear 45aattached to the projecting outer end of the shaft and a worm 49bengaging said gear.

In order to facilitate insertion and removal of shaft 45 with the Wiperthus carried thereby, a radial slot 55 is cut in hub 35, such slot beingof proper width to permit the ready passage therethrough of the blade,however constructed. When the blade is in its operative position, asshown in Figs. 2 and 3, such passage will be closed by a plug 55 that isheld in place by meansof a flange on the bushing 35a.

While the wiper assembly must be inserted before the brush is placed inits bearings, thereafter the angular adjustment of the wiper can be madewithout disturbing the brush mounting. Likewise, the feeder tube 45 canbe inserted and removed, as can also the reciprocable clean-out shaft orplug 41, all without disturbing the brush set-up.

The manner in which a brush constructed as just described isutilized ina brushing operation such as that illustrated in Fig. 1 will now be setforth. Assuming the open end of feed tube 45 f to be connected with asuitable supply of granular abrasive, or other material such as morefully set forth later herein, which may be carried by a stream of air orother suitable vehicle moving at proper velocity, such abrasive or thelike will be carried into the hollow interior of the brush body andthere be subjected to the centrifugal force occasioned by the high rateof rotation of such body when the brush is in operation. The effect willbe to cause the abrasive to flow through the perforations 33 in shell3'! and thence to discharge the same at an accelerated rate of movementthrough the stranded body of brush material. effectively controlled byrotating the feed tube so as to vary the angular direction of theopenings therein, through which such abrasive is supplied to the hollowinterior of the brush. Thus, for example, as such material is dischargedfrom the stranded brush body, it can be directed onto the surface of thesheet being brushed along the line of contact of the brush therewith, orin ad- Vance of such line, as desired. Such direction of discharge maybe further controlled by utilizing the wiper 52 as a deflector, to whichpurpose it is equally well adapted. In other words, by proper angularadjustment of the feed tube and of such wiper thus serving as adeflector, the angle at which the major portion of the abrasive will bedischarged from the brush can be fairly closel controlled.

It is not necessary of course that all of the particles of abrasiveshould fall within a defined area on the sheet, but merely that themajor portion thereof should do so. In order to catch such particles asmay be thrown beyond the desired area, any suitable form of enclosure orguard may be employed. It will be further understood that whilereference has been made in the foregoing description of the operation ofmy improved brush to the use of a granular abrasive conveyed b a streamof air, other media, including a suitable liquid, may be employed, suchliquid carrying the abrasive being discharged in the same manner.Moreover, for certain purposes the material supplied to the brush forthe purpose of thus being centrifugally discharged therefrom may consistwholly of a liquid medium capable of having a beneficiating effect onthe surface of the sheet as it is being brushed.

While my improved method and. apparatus for surface beneficiating metalsheets and the like has been described with special reference to theremoval of scale and like closely adherent coatings, no limitation tosuch particular use is to be implied. Thus, by employing other forms ofdiscrete hard particles instead of granular abrasive, e. g. peeningpellets of properly selected size, such method and apparatus may beequally well employed in the peening treatment of sheets and like metalparticles.

In peening practice as at present carried out, while the impact of thepellets or shot has the desired effect of relieving surface tensions andotherwise beneficiating the surface of the article being treated, thereis at the same time produced a disadvantageous effect arising from thepresence of the crushed cementite and other constituents of steel. Wherethe broken fragments of such materials, which are relatively hard,remain on the surface, not only is the peening action interfered withbut the surface itself may be permanently marred. However, by combiningwith the impact action of peening pellets a brushing action such as I amable to obtain, these objectionable products are immediately removed anda much more perfect surface condition obtained.

The direction of such discharge can be' Where peening pellets areemployed, they will of course be fed onto the work-piece by means of thebrush so as to be projected therefrom by centrifugal action of thelatter in the same manner as the granular abrasive material previouslyreferred to. Furthermore, as has hereinbefore been pointed out, myimproved construction of brush and the method involved in its use may befound quite advantageous where instead of thus feeding discrete hardparticles through the brush, other kinds of beneficiating materials, e.g. in liquid form, are thus applied to the surface of the article beingtreated, without carrying any granular abrasive or other additionalmaterial.

While the means and method hereinbefore described for centrifugallydischarging abrasive or other beneficiating material onto the surfacebeing treated, viz. by feeding the same into the interior of a brushrotating at high speed, thence to pass radially outwardly through thestranded brush material, are considered preferable, I have found a likeeffect may be obtained by supplying such material at the proper point orpoints on the surface of such a brush as more fully set forth in myco-pending application Serial No. 126,408, filed Novemer 9, 1949.

The term surface beneficiation as employed herein is to be understood ascomprehending any of the several forms of treatment mentioned, e. g.cleaning, polishing, scale removal and relieving surface tension.

Referring now more particularly to Fig. 4, the apparatus in the formtherein disclosed comprises two rolls 92 and 93 about which the metalstrip 94 is adapted to pass in such manner that each side of the stripwill be respectively subjected to the action of brushes 95 and 96. Thesebrushes will generally be rotating at speeds in the vicinity of 9000 F.P. M. and their directions of rotation will desirably be periodicallyreversed, the rate of travel of the strip ordinarily being sufficientlyslow that no consideration need be given thereto in this connection. Thestrip of course is moving at a much lower relative speed.

The end. of the strip approaches the machine sliding along conveyor 91until it strikes large roll 92 whereupon the end of the strip isdeflected and received between the surface of such roll and a smallauxiliary roll 93 carried by a spring-backed mount 99 provided with anadjustable stop !00 operative to limit maximum movement of roll 98.Rotation of roll 92, which is driven from any suitable power source,then operates to pull the strip into the nip of the two rolls and thestrip is driven forward against roll IOI which is mounted ina mannersimilar to roll 98 and very close to the latter (detailed mounting meansnot shown for purposes of clarity). The sheet is then driven onwardbetween rolls 9.2 and .IOI and becomes arcuately bent through theinteraction of rolls 92, 98 and IOI to a radius substantially conformingto the surface of roll 92. The sheet next passes under a spring loadedshoe I02 carrying one or more rollers I03 similarly operable to bearupon the sheet. The smooth curved surface of shoe I02 adjacent roll 92is sufficiently removed from roll 92 to afford ample clearance forpassage of the strip but serves to deflect such strip should the latterfail closely to conform to the surface of roll 92. Spring I04 iseffective to cause rollers I03 to bear on the strip with considerablepressure in order to maintain the latter in tight engagement with roll92 as it passes beneath brush 95. A second spring loaded shoe I05provided with similar rollers I06 cooperates in maintaining the strip inclose engagement with roll 92.

The strip then passes over pulley roller I 01 and follows conveyor I09to roll 93 where it passes between roll 93 and rolls 98, 10!, I03, and[09, these rolls corresponding in mounting and function to the similarrolls above described. Deflector I I starts the strip from roll 93whereupon it passes between rolls Ill, H2, and H3 which have astraightening effect upon the strip which now resumes its course in itsoriginal direction along conveyor H4. driven similarly to roll 92,either through a train of gears or alternatively by means of a separateelectric motor, for example, which may be caused to turn roll 93 at aslightly greater speed than roll 92 to aid in keeping the strip tight.

Directly below the point of tangency of roll 92 and brush 95 is anexhaust collector H5 adapted to receive the particles such as scaledischarged by the action of the brush. An appropriate blower H6 forcesthe scale along duct Ill to screen H8 where the larger particles arecaught and collected in trap H9. The finer particles of scale arecarried to hopper I20 from the bottom of which they are fed orpreferably forced to the outer periphery of the rapidly rotating brush95. In other words, the material in question may thus be supplied to thework either by a controlled gravity feed of any usual type or by an airblast of familiar construction, and the material maybe thus dischargedagainst the surface of the strip being treated with only a portion beingdelivered to the periphery of the brush prior to engagement with suchstrip. A similar system, the parts of which are identified by likenumerals, is provided for brush 96. Since the details of the system formno part of the present invention, it has been considered unnecessary toillustrate other than in diagrammatic fashion the specific constructionof feeding means, whether gravity or air blast, thus associated withhoppers I20.

This application is a continuation-in-part of I my co-pendingapplication Serial No. 668,391

filed May 9, 1946, in turn a continuation-in-part of Serial No. 632,831filed December 5, 1945, and Serial No. 437,648 filed April 4, 1942; andalso of my co-pending application Serial No. 126,408 filed November 9,1949. Such applications Serial Nos. 437,648; 632,831; and 668,391 havebeen abandoned without prejudice in favor of this present application.

Other modes of applying the principle of the invention may be employed,change being made as regards the details described, provided thefeatures stated in any of the following claims or the equivalent of suchbe employed.

I therefore particularly point out and distinctly claim as my invention:

1. In a method of removing scale from a metal sheet, the steps whichcomprise flexing the sheet, brushing the convex face of the latter, andsimultaneously supplying to the face thus being brushed an abrasiveconsisting substantially entirely of previously removed scale particles.

2. In a method of removing scale from a metal sheet, the steps whichcomprise flexing the sheet, brushing the convex face of the latter,collecting the particles of scale removed from such sheet by suchbrushing operation, and supplying such particles to the face of thesheet while subjected to such brushing step.

Roll 93 may be to such brush in such relation as to be projected therebyonto such convexly flexed surface.

5. The method of removing scale from a metal sheet which comprisesprogressively flexing such sheet convexly to raise the edges of thescale particles, and forcefully projecting abrasive material in ageneral tangential direction onto such convexly flexed portion of thesheet.

6. The method of removing scale from a metal sheet which comprisesprogressively flexing such sheet convexly to raise the edges of thescale particles, brushing such convexly flexed portion of the sheetnormal to the line of flexing throughout such line, and simultaneouslyforcefully projecting abrasive material in a general tangentialdirection onto such convexly flexed portion of the sheet.

7. The method of removing scale from a metal sheet which comprisesprogressively flexing such sheet convexly to raise the edges of thescale particles, brushing such convexly flexed portion of the sheetnormal to the line of flexing throughout such line, and simultaneouslysupplying abrasive material to such brush in such relation as to beprojected thereby onto such convexly flexed portion of the sheet.

RUBEN O'. PETERSON.

References Cited in the file of this patent UNITED STATES PATENTS NameDate Wooster Oct. 6, 1868 Hall et a1 Feb. 5, 1884 Buckman Apr. 28, 1891Lindsey Dec. 29, 1891 Nelson Feb. 21, 1893 Muller Nov. 10, 1903Broderick Oct. 29, 1907 Miller Oct. 23, 1923 Miller Nov. 20, 1923McCrery Oct. 25, 1932 MacGregor Oct. 30, 1934 Berger Aug. 11, 1936 QuinnMay 23, 1939 Lynch May 23, 1939 Minich Aug. 29, 1939 Jesser Sept. 19,1939 Coddington May 14, 1940 Hershey et al Nov. 12, 1940 Wallace July15, 1941 Quigley et al Apr. 7, 1942 Wood Apr. 14, 1942 Stanier et al May4, 1943 Pecsok Nov. 23, 1943 Yoder Dec. 25, 1945 Barnes Oct. 28, 1947Stone Dec. 16, 1947 Anderson Apr. 18, 1950 Number FOREIGN PATENTS Number

